The present invention relates to a stabilizing device for a heavy vehicle, such as a truck or the like.
A stabilizing device of such kind is known from DE 28 49 015. According to this stabilizing device, two supporting stabilizer arms are constituted by adjustable hydraulic dampers. Hereby the reference level of the dampers may be adjusted and thereby providing an improved driving comfort as the suspension and the damping may be adjusted to the actual load of the vehicle.
Examples of other axle suspension devices including roll stabilizing devices are known from EP 0 430 368 and WO 90/13450.
The stabilizing device provides a roll stabilizing effect of the vehicle. As heavy vehicles such as trucks are more often air suspended the requirements of the anti-roll bar system are increased. Likewise as the trucks typically have the centre of gravity which is relatively high, this increased the demand for what the roll stabilizing system is capable of performing.
As trucks are being fitted with air suspension systems, it is also possible to provide a manual level control system with pre-programmed loading dock heights to facilitate the handling of goods to be loaded and unloaded from the vehicle. However, the roll stabilizing system actually counteracts this chassis lifting or lowering. Moreover, the range between the lowermost and the highest possible position of the chassis level are often dictated by the other components present, such as air bellows for the air suspension, etc. and the size of the components. This presents a limitation which means that the chassis level movement is not fully satisfactory with the users' demands by the present trucks.
As truck users demand the possibility of an increase in the level for lifting or lowering the chassis during loading and unloading, it is desirable to provide a stabilizing device of the initially mentioned kind which allows for an increase in the possible chassis lifting range.
By the provision of at least one said stabilizer arm which is attached to a stabilizer anchor means which in turn is mountable in a vehicle frame, wherein the stabilizer anchor means comprises a stabilizer arm attachment point which is displaceable so as to enable the effective length of the stabilizer arm to be adjusted within a predetermined interval, a stabilizer system may be provided which during driving actively is capable of changing the stabilizer forces and can facilitate a larger lifting range for the chassis level.
By the invention, it is realized that by providing a displaceable attachment point for the stabilizer arm, there is provided a possibility of effectively arranging a longer leveling stroke in the (telescopic) stabilizer arm resulting in an increase in achievable levels of the chassis height. Similarly, for smaller trucks, the chassis lifting may be provided as the stabilizing device according to the invention increases the rear approach angle as each of the arm components may be reduced in size. The stabilizing device according to the invention is applicable in relation to both front and rear axle stabilizer installation. Furthermore, the overhang can be reduced by allowing a tighter installation.
Another advantage of the invention is that stabilizer anchors means arranged on each side of the vehicle axle can be independently operated, which provides a possibility of keeping the truck horizontal in the sideways direction when loading and unloading. This is particularly advantageous in relation to delivery trucks in the city which during loading or unloading often must be parked with some of the wheels on the sidewalk, i.e. in a different ground level. By the invention it becomes possible to bring the vehicle chassis in a horizontal position when the vehicle is parked at an uneven or sloping surface for loading or unloading which in particular improves the loading or unloading of trolleys or other goods that are wheeled in or out of the truck.
In a preferred embodiment of the invention, the stabilizer anchor means comprises a pivot member with a stabilizer arm attachment point which is positioned off-set from the pivot centre of the pivot member. Hereby, the upper attachment point of the stabilizer arm can be moved up or down by pivoting the pivot member.
Preferably, the stabilizer device further comprises or cooperates with control means for controlling the pivoting of the pivot member and thereby controlling the chassis lifting motion and/or roll characteristics of the vehicle. Hereby, the position of the stabilizer arm and thereby effectively the length of the stroke may be adjusted. The control means may comprise an automatic adjustment function, e.g. during driving to prevent chassis rolls for instance when driving through curves. Furthermore, the control means may comprise manual adjustment means for leveling the chassis when the vehicle is parked. Accordingly, the control means can be connected to or constituted by an already existing vehicle chassis control system of a vehicle, and adapted to allow displacement of the stabilizer arm attachment point during driving of the vehicle. As an alternative or as a supplement, the control means are connected to or constituted by such a vehicle chassis control system and adapted to prevent displacement of the stabilizer arm attachment point during driving.
In a further preferred embodiment of the invention, the stabilizer arms on each side of the vehicle frame can be independently controlled by said control means in order to achieve a predetermined level and roll characteristics of the vehicle chassis.
Further advantages and advantageous features of the invention are disclosed in the following description.